New derivatives of substituted piperazines

ABSTRACT

A process for obtaining substituted piperazine derivatives, notably an amino-alcohol derivative for therapeutic use, is described. At least one epoxide, particularly 3-phenyl, 3-methoxy, 1,2propylene oxide is reacted on a substituted piperazine, particularly 1-(2-phenyl, 2-methoxy)ethyl piperazine. The invention notably relates to a new amino-alcohol formula (I). as well as the addition salts thereof with organic or inorganic acids which are pharmaceutically acceptable. The application of the compound of formula (I) in medicines having antitussive, mucolytic and eupneic actions.

United States Patent [191 Mauvernay et al.

[ Feb.27,1973

1541 1 NEW DERIVATIVES or SUBSTITUTED PIPERAZINESH [75] Inventors: Roland Yves Mauvernay, Riom, Norbert Busch, Puy de Dome, Jacques Moleyre, Menetrol, Jacques Simond,

V Charnalieres, all of France [73] Assignee: Societe Anonyrne Centre Europecn De Recherches Mauvernay, Riom, France 221 Filed: Feb. 23, 1971 211 Appl.No.: 118,077

[30] Foreign Application Priority Data 3,036,076 5/1962 3,378,553 4/1968 3 ,448,192 6/1969 Mauvernay ..260/268 I-I FOREIGN PATENTS OR APPLICATIONS 12/1968 France ..260/268 R Primary Examiner-Donald G. Daus Attorney-Melville, Strasser, Foster & Hoffmann [57] ABSTRACT A process for obtaining substituted piperazine derivatives, notably an amino-alcohol derivative for therapeutic use, is described.

At least one epoxide, particularly 3-phenyl, 3-methoxy, 1,2-propylene oxide is reacted on a substituted piperazine, particularly l-(2-phenyl, 2-methoxy)ethyl piperazine. The invention notably relates to a new amino-alcohol formula (I).

H OCH;

as well as the addition salts thereof with organic or inorganic acids which are pharmaceutically acceptable.

The application of the compound of formula (I) in medicines having antitussive, mucolytic and eupneic actions.

A 2 Claims, No Drawings 1 2 NEW DERIVATIVES F SUBSTITUTED than 100 C are used. Substituted alkylene-oxides may PIPERAZINES be used alone or in combinations. Substantially equimolar amounts of reactives are usually suitable. The present invention relates in a general manner to Th invention will b illustrat d more rtic larl a Process for Qbtaining substituted piperazine deriva' 5 hereinafter with reference to a compound which may i relates more f p y to amimyalcohol be obtained by such a process and which consists of an derivative and the addition salts thereof with phari al oh l fth generalformula;

maceutically acceptable organic or inorganic acids. The invention also relates to the applications of said (I) amino-alcohol as a medicament, and particularly as an O 5 antitussive agent. ocrr French Pat. n7' 304 M has already described compounds of the general formula: Compound (I) is obtained according to the process of the invention by the condensation of l-[2-phenyl,2-

methoxy] ethyl piperazine with 3-phenyl, 3-methoxy,

. a m X 0 32: 1,2-propylene oxide according to the following reac- CH3 0 CH;

OCH: OH bong wherein R is a straight or branched chain alkyl radi- For the preparation of l-[2-phenyl,2methoxy] ethyl L 2 s. identical or diffelfim, epresenting piperazine, referring advantageously to the process notably either hydrogen, or an alk xy or alke xy a described in the aforesaid patent n7304 M, which is inkyl. troduced into the present description as a reference.

These compounds possess bronchospasmolytic pro- I order to prepare 3-phenyl, 3-methoxy, 1,2. pertlesy can be P p y a three'stage Process propylene-oxide, the process which is the object of which is described in the aforesaid patent. In a first French 6944213 may be used Said process Stage, -p yb z'alkoxfi-ethylbromide is Pf which is carried out in two stages starting with cinnamby alkoxytfronlatlon of Styrene by 9 tertlo'b'utyl ic alcohol, can be illustrated by the following reaction hypobromite in the alcanol corresponding to R; m a diagram in h case of 3-phenyl, 3-methoxy l 2- second stage, I-(Z-phenyl, 2-alkoxy)-ethylpiperazine propylene oxide. by the action of piperazine on the product of stage l,in a third stage a Mannich reaction is efiected between the product of stage 2, formaldehyde and acetophenone bearing the substituants corresponding 40 to R R and R and finally, the product of stage 3 is reduced by means of sodium borohydride.

FIRST STAGE French Pat. 5390 M also described compounds hav- E ins, notab|y the f l @CH=CHCH:OH R-OH OH3;CO Br CH3 C) -oH-oH2-N NCH2CH2'C-Ar l U II R 0 wherein R is a lower alkyl radical and Ar is an aromatic s radical, particularly the phenyl radical. @CHCHCH2OH CH;;COH

These compounds possess antitussic properties. To Br CH3 obtain them, a l-(2-phenyl-Z-alkoxy)-ethyl-piperazine is reacted with a ketone and formol (Mannich reaction) or with 4-vinyl-pyridine, according to the signification of R in the preceding formula. The starting l-( 2- phenyl-2valkoxy)-ethyl-piperazine is obtained by the STAGE action of piperazine on 2-phenyl-2-alkoxy-ethyl bromide, which is obtained by the reaction of vinylbenzene on the corresponding ROl-l alcohol in the presence of tertio-butyl hypobromite. G The invention relates to a process for obtaining new derivatives of substituted piperazine derivatives characterized in that at least one epoxide is reacted on a substituted piperazine.

Generally speaking, the process can be carried out in a solvent medium and at a moderately high tempera- C) BrNa 2 ture. For example, ethanol and temperatures lower 00113 0 CII-Cll-Cll20ll I NllCll l ()Cllalil Compound (I) has remarkable antitussive properties as well as a certain bronchospasmolytic activity. It further has the advantage, compared with the compounds described in French Pat. n" 390 M, of giving addition salts which are very stable in aqueous solution. 5 The example which follows illustrates the synthesis of compound (1).

EXAMPLE In a reactor provided with a mechanical stirrer, a reflux refrigerant and a thermometer, there is introduced:

393 g 1- [2-phenyl, 2-methoxy]ethyl piperazine 22 g 3-phenyl, B-methoxy propylene oxide in 750 ml of absolute ethanol.

When the slightly exothermic reaction (rise in temperature of about degrees) has ceased, heating is effected for 1.5 hours at 60 C. The product is then cooled to 4 C and left to crystallize for about 12 hours. The precipitate is centrifugated then recrystallized in 500 ml of absolute ethanol.

420 g of the desired compound (I) is thus obtained in the form of a white, crystalline powder.

Melting point: 83 C Elementary analysis:

N% c%' 11% Calculated 7,28 71,86 8,39 Found 7,25 71,51 8,20

PHARMACODYNAMIC STUDY RELATING TO COMPOUND (I) 1. Accute Toxicity This was sought for by the oral method in the mouse.

The LD 50, calculated according to B. BEHRENS and C. KARBER [Arch. F. Exp. Path. Pharm. 177:379( 1935) gave the following result:

S5 LD 50 550 mg/kg.

2. Antitussive Action Studied on the Cat The cat is anesthetized with ether and tracheotomized. Coughing spasms are induced by the stimulation of a laryngeal nerve. After administration of the product to be studied, new stimulations permit the inhibition obtained and its duration to be evaluated. [DOMENJOZ R. Arch.Exp. Pathol. V. Pharmacol,2l5 19 (1952)]. The results obtained by this method are shown in table I.

TABLE] Dose and Maximum of Time lag before 7, T Dis appearmethod of inhibition C 7 W the appearance of ance of the I administration maximal inhibition activity 2 mglkg l.V. 77 tn 6 minutes H 28 minutes 5 mglkg 1D. 21 20 minutes 27 minutes 10 mg/kg ID. 84 21 minutes minutes TABLE II Dose and Maximum of Time lag before Disappearmethod of inhibition the appearance ance of the administration of maximal activity inhibition 10 mglkg ID. 52% 25 minutes 85 minutes 20 mglkg ID. 94% 25 minutes minutes 3. IN VIVO" ANTIHISTAMIC ACTION ON THE GUINEA PIG This action was investigated by the study of antagonism with respect to histamine that as bronchoconstrictor agent.

a. Protection with Respect to Bronchospasms Induced by a Histamine Aerosol The bronchospasm is induced in the guinea pig by a histamine aerosol (solution at 3%0 in a 20 percent glycerine solution).

The period of time to the appearance of the accute crisis of dyspnea is noted for each animal. Twenty four hours later the animals are subjected to a second exposure to the aerosol, 45 minutes after treatment with the substance being studied, and the period of time to the appearance of the crisis of dyspnea is also noted.

The protection afforded by the substance tested is estimated by the increase of the duration of exposure to the bronchoconstrictor aerosol. An increase of more than ten minutes with respect to the control time is considered as a total protection.

In the case of the compound studied, an ED 50 value, given orally, of 45 mg/kg is obtained.

b. Protection with Respect to Mortal Bronchospasm Induced by an Intravenous Injection of Histamine The control animals are male guinea pigs which are injected intravenously with 2.5 mglkg histamine (this dose is five times the minimal mortal dose, which is 0.5 l g)- The time the crisis starts is noted, as well as the time of death.

The animals treated received the product by oesophageal intubation, forty five minutes before the intravenous injection of histamine.

For a dose of the compound studied of 25 mglkg given by mouth, 4 animals out of 10 are protected.

4. IN VITRO SPASMOLYTIC ACTION ON GUINEA PIG ILEUM The ileum is removed from a guinea pig killed by bleeding. A 2 to 3 centimeter long fragment is placed in a tank containing the Tyrode solution maintained at 30 C and oxygenated.

The ileum is stretched between the support on the bottom of the tank and the recording level. The recording is made on a cylinder coated with lamp black.

Determination is carried out of the concentration of the product necessary to decrease or abolish the contraction induced by:

---2.l' g/l histamine 5 l 0- g/l acetylcholine I ,6.10' g/l baryum chloride.

When compound (I) is tested, the ED 50 values given in table III below are obtained:

The therapeutic indications of compound (I) result from the preceeding considerations. It was found that compound (I) and the compositions containing it, particularly the addition salts thereof with pharmaceutically acceptable acids, possess antitussive, mycolytic and eupneic actions.

The medicamentscontaining, as an active agent, compound (I) or at least one of the acid addition salts thereof can be administered: orally, in the form of tablets, gellules, capsules, soluble granules, drops, syrup containing 40 to mg of active compound per dosage unit. by the rectum, in the form of suppositories or rectal capsules, containing 100 to 200 mg of active compound per dosage unit, associated with the excipients usually used in such preparations.

What we claimed is:

1. The substituted piperazine compound consisting of an amino alcohol of the formula (I) 00113 H OCH3 

2. Salts according to claim 1 characterized in that they are hydrosoluble. 